The analgesic effect of Capsicum frutescens in streptozotocin-diabetic rats using formalin test

Diabetic rats in long-term display an augmented nociceptive response to chemical, mechanical, and thermal stimuli. Furthermore, hyperalgesia is one of the major symptoms of diabetic neuropathy in some patients. Considering the antidiabetic potential of pepper, this study was carried out to evaluate the possible analgesic effect of pepper-mixed food intake in male streptozotocin-induced diabetic rats. For this purpose, Male Wistar rats (n = 46) were randomly divided into control, pepper-treated control, salicylate-treated control, diabetic, and pepper-treated diabetic groups. At the end of the experiment, nociceptive response was evaluated in both acute and chronic phases of the standard formalin test. The results showed that there was a significant increase in the number of pain scores in both acute and chronic phases in diabetic rats (P<0.05), and administration of pepper for one month did significantly reduce the pain score in both phases of the test (P<0.01). In contrast, sodium salicylate as positive control only reduced this score in the second phase (P<0.05). It can be concluded that oral administration of pepper for one month through central and peripheral mechanisms could attenuate the nociceptive response in diabetic rats.